<template>
  <div>
    <v-data-table
      :headers="headers"
      :items="desserts"
      :sort-by.sync="sortBy"
      :sort-desc.sync="sortDesc"
      class="elevation-1"
    ></v-data-table>
    <div class="text-center pt-2">
      <v-btn
        color="primary"
        class="mr-2"
        @click="toggleOrder"
      >
        Toggle sort order
      </v-btn>
      <v-btn
        color="primary"
        @click="nextSort"
      >
        Sort next column
      </v-btn>
    </div>
  </div>
</template>

<script>
  export default {
    data () {
      return {
        sortBy: 'fat',
        sortDesc: false,
        headers: [
          {
            text: 'Dessert (100g serving)',
            align: 'start',
            value: 'name',
          },
          { text: 'Calories', value: 'calories' },
          { text: 'Fat (g)', value: 'fat' },
          { text: 'Carbs (g)', value: 'carbs' },
          { text: 'Protein (g)', value: 'protein' },
          { text: 'Iron (%)', value: 'iron' },
        ],
        desserts: [
          {
            name: 'Frozen Yogurt',
            calories: 159,
            fat: 6.0,
            carbs: 24,
            protein: 4.0,
            iron: '1%',
          },
          {
            name: 'Ice cream sandwich',
            calories: 237,
            fat: 9.0,
            carbs: 37,
            protein: 4.3,
            iron: '1%',
          },
          {
            name: 'Eclair',
            calories: 262,
            fat: 16.0,
            carbs: 23,
            protein: 6.0,
            iron: '7%',
          },
          {
            name: 'Cupcake',
            calories: 305,
            fat: 3.7,
            carbs: 67,
            protein: 4.3,
            iron: '8%',
          },
          {
            name: 'Gingerbread',
            calories: 356,
            fat: 16.0,
            carbs: 49,
            protein: 3.9,
            iron: '16%',
          },
          {
            name: 'Jelly bean',
            calories: 375,
            fat: 0.0,
            carbs: 94,
            protein: 0.0,
            iron: '0%',
          },
          {
            name: 'Lollipop',
            calories: 392,
            fat: 0.2,
            carbs: 98,
            protein: 0,
            iron: '2%',
          },
          {
            name: 'Honeycomb',
            calories: 408,
            fat: 3.2,
            carbs: 87,
            protein: 6.5,
            iron: '45%',
          },
          {
            name: 'Donut',
            calories: 452,
            fat: 25.0,
            carbs: 51,
            protein: 4.9,
            iron: '22%',
          },
          {
            name: 'KitKat',
            calories: 518,
            fat: 26.0,
            carbs: 65,
            protein: 7,
            iron: '6%',
          },
        ],
      }
    },
    methods: {
      toggleOrder () {
        this.sortDesc = !this.sortDesc
      },
      nextSort () {
        let index = this.headers.findIndex(h => h.value === this.sortBy)
        index = (index + 1) % this.headers.length
        this.sortBy = this.headers[index].value
      },
    },
  }
</script>
